From 516280e735b034216de97eb7ba080ec6acbfc58f Mon Sep 17 00:00:00 2001 From: Jarod Wilson Date: Thu, 22 Jan 2009 19:58:15 +1100 Subject: [PATCH] crypto: ccm - Fix handling of null assoc data Its a valid use case to have null associated data in a ccm vector, but this case isn't being handled properly right now. The following ccm decryption/verification test vector, using the rfc4309 implementation regularly triggers a panic, as will any other vector with null assoc data: * key: ab2f8a74b71cd2b1ff802e487d82f8b9 * iv: c6fb7d800d13abd8a6b2d8 * Associated Data: [NULL] * Tag Length: 8 * input: d5e8939fc7892e2b The resulting panic looks like so: Unable to handle kernel paging request at ffff810064ddaec0 RIP: [] :ccm:get_data_to_compute+0x1a6/0x1d6 PGD 8063 PUD 0 Oops: 0002 [1] SMP last sysfs file: /module/libata/version CPU 0 Modules linked in: crypto_tester_kmod(U) seqiv krng ansi_cprng chainiv rng ctr aes_generic aes_x86_64 ccm cryptomgr testmgr_cipher testmgr aead crypto_blkcipher crypto_a lgapi des ipv6 xfrm_nalgo crypto_api autofs4 hidp l2cap bluetooth nfs lockd fscache nfs_acl sunrpc ip_conntrack_netbios_ns ipt_REJECT xt_state ip_conntrack nfnetlink xt_ tcpudp iptable_filter ip_tables x_tables dm_mirror dm_log dm_multipath scsi_dh dm_mod video hwmon backlight sbs i2c_ec button battery asus_acpi acpi_memhotplug ac lp sg snd_intel8x0 snd_ac97_codec ac97_bus snd_seq_dummy snd_seq_oss joydev snd_seq_midi_event snd_seq snd_seq_device snd_pcm_oss snd_mixer_oss ide_cd snd_pcm floppy parport_p c shpchp e752x_edac snd_timer e1000 i2c_i801 edac_mc snd soundcore snd_page_alloc i2c_core cdrom parport serio_raw pcspkr ata_piix libata sd_mod scsi_mod ext3 jbd uhci_h cd ohci_hcd ehci_hcd Pid: 12844, comm: crypto-tester Tainted: G 2.6.18-128.el5.fips1 #1 RIP: 0010:[] [] :ccm:get_data_to_compute+0x1a6/0x1d6 RSP: 0018:ffff8100134434e8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8100104898b0 RCX: ffffffffab6aea10 RDX: 0000000000000010 RSI: ffff8100104898c0 RDI: ffff810064ddaec0 RBP: 0000000000000000 R08: ffff8100104898b0 R09: 0000000000000000 R10: ffff8100103bac84 R11: ffff8100104898b0 R12: ffff810010489858 R13: ffff8100104898b0 R14: ffff8100103bac00 R15: 0000000000000000 FS: 00002ab881adfd30(0000) GS:ffffffff803ac000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: ffff810064ddaec0 CR3: 0000000012a88000 CR4: 00000000000006e0 Process crypto-tester (pid: 12844, threadinfo ffff810013442000, task ffff81003d165860) Stack: ffff8100103bac00 ffff8100104898e8 ffff8100134436f8 ffffffff00000000 0000000000000000 ffff8100104898b0 0000000000000000 ffff810010489858 0000000000000000 ffff8100103bac00 ffff8100134436f8 ffffffff8864c634 Call Trace: [] :ccm:crypto_ccm_auth+0x12d/0x140 [] :ccm:crypto_ccm_decrypt+0x161/0x23a [] :crypto_tester_kmod:cavs_test_rfc4309_ccm+0x4a5/0x559 [...] The above is from a RHEL5-based kernel, but upstream is susceptible too. The fix is trivial: in crypto/ccm.c:crypto_ccm_auth(), pctx->ilen contains whatever was in memory when pctx was allocated if assoclen is 0. The tested fix is to simply add an else clause setting pctx->ilen to 0 for the assoclen == 0 case, so that get_data_to_compute() doesn't try doing things its not supposed to. Signed-off-by: Jarod Wilson Acked-by: Neil Horman Signed-off-by: Herbert Xu --- crypto/ccm.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/crypto/ccm.c b/crypto/ccm.c index 7cf7e5a6b78..c36d654cf56 100644 --- a/crypto/ccm.c +++ b/crypto/ccm.c @@ -266,6 +266,8 @@ static int crypto_ccm_auth(struct aead_request *req, struct scatterlist *plain, if (assoclen) { pctx->ilen = format_adata(idata, assoclen); get_data_to_compute(cipher, pctx, req->assoc, req->assoclen); + } else { + pctx->ilen = 0; } /* compute plaintext into mac */